Generally, parabolic antennas have been used for communication with geostationary satellites. Basically, however, a parabolic antenna is capable of corresponding to electromagnetic waves from only one direction. Therefore, the setting of the parabolic antenna is very difficult because three axes of a vertical direction (elevation angle), a transverse direction (azimuth angle), and an inward direction of antenna face must be adjusted for its installation. In addition, the parabolic antenna is inferior with respect to electrical and mechanical durability against a strong wind since a mast must support against the wind loading during a strong wind that blows against the dish face, and thereby it may occasionally suffer from electromagnetic interference because of bending of the mast. Also, if a firm mast is to be installed, it is susceptible to problems in terms of cost and view and to installation regulations in Europe and America as well as in Japan.
In order to solve these problems, the wall type lens antenna equipment disclosed in Japanese Patent Application Publication No. 2003-110350 and Japanese Patent Application Publication No. 2003-110352 has a reflector which has a diameter larger than the lens diameter of a hemispherical Luneberg lens made of dielectric and which is provided on the cross-section made by halving a globular shape of the hemispherical Luneberg lens, wherein the reflector is to be attached to a wall or the like substantially perpendicularly.
The above-mentioned lens antenna equipment has a mechanism in which the adjustment of positioning a primary feed at the time of installation is simplified. However, the mechanism was yet to be further improved since its performance for positioning adjustment was unsatisfactory in the case of communication with a geostationary satellite, particularly in the case of a plurality of geostationary satellites.
That is, in the case of the antenna equipment which is installed combining a hemispherical Luneberg lens and a reflector in a vertical arrangement, it is necessary to obtain information on the directions of a wall, a verandah, a fence, etc. where it is to be installed. However, it is not easy to judge them on the spot. If such a wall or the like where the antenna equipment is to be installed is located straightly facing equipment with which communication is to be established, it is convenient, but otherwise it is necessary to adjust the positioning of the primary feed, depending on the differences in the direction with respect to the equipment to be communicated with.
The antenna equipment disclosed in the above-mentioned patent applications is structured such that the position of a primary feed is determined at the focus of the lens by separately adjusting the longitude, latitude, and direction thereof, respectively. Thus, it takes time to achieve such adjustment. Particularly, when it is necessary to make the adjustment corresponding to a plurality of geostationary satellites, it is difficult to accomplish the adjustment of the positioning because the respective positions of focus of the geostationary satellites must be searched for at the site since the direction of the wall or the like is obscure.